diff --git a/CHANGELOG.md b/CHANGELOG.md
index baf1ad80..056b78d6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,7 +3,6 @@
 * Adds email and ttl to CLI zone list output
 * Adds `ZoneApi.iterateByName()` to support lookups
 * Adds `-n` parameter to CLI zone list
-* `supportsDuplicateZoneNames()` means `Zone.qualifier()` is present
 * Deprecates `Zone.idOrName()` as `Zone.id()` cannot be null
 * Documents third-party provider process
 * Publishes model and core test jars
diff --git a/cli/src/main/java/denominator/cli/Denominator.java b/cli/src/main/java/denominator/cli/Denominator.java
index 0548611f..8f8c2837 100644
--- a/cli/src/main/java/denominator/cli/Denominator.java
+++ b/cli/src/main/java/denominator/cli/Denominator.java
@@ -385,8 +385,7 @@ public Iterator<String> doRun(final DNSApiManager mgr) {
       return Iterators.transform(zones, new Function<Zone, String>() {
         @Override
         public String apply(Zone input) {
-          return format("%-24s %-36s %-19s %-36s %d", input.id(), input.name(),
-                        input.qualifier() != null ? input.qualifier() : "", input.email(),
+          return format("%-24s %-36s %-36s %d", input.id(), input.name(), input.email(),
                         input.ttl());
         }
       });
diff --git a/cli/src/test/java/denominator/cli/DenominatorTest.java b/cli/src/test/java/denominator/cli/DenominatorTest.java
index 4b70d98a..bc8b807d 100644
--- a/cli/src/test/java/denominator/cli/DenominatorTest.java
+++ b/cli/src/test/java/denominator/cli/DenominatorTest.java
@@ -75,7 +75,7 @@ public void listsAllProvidersWithCredentials() {
   @Test // denominator -p mock zone list
   public void testZoneList() {
     assertThat(new ZoneList().doRun(mgr)).containsExactly(
-        "denominator.io.          denominator.io.                                          admin.denominator.io.                86400"
+        "denominator.io.          denominator.io.                      admin.denominator.io.                86400"
     );
   }
 
diff --git a/core/src/main/java/denominator/Provider.java b/core/src/main/java/denominator/Provider.java
index abe9be49..d90cb7ae 100644
--- a/core/src/main/java/denominator/Provider.java
+++ b/core/src/main/java/denominator/Provider.java
@@ -5,7 +5,6 @@
 import java.util.Set;
 
 import denominator.model.ResourceRecordSet;
-import denominator.model.Zone;
 
 /**
  * Metadata about a provider of DNS services.
@@ -70,7 +69,7 @@ public interface Provider {
   Map<String, Collection<String>> profileToRecordTypes();
 
   /**
-   * Zones have {@link Zone#qualifier()} set, as duplicate zones can exist with the same name.
+   * Duplicate zones can exist with the same name.
    */
   boolean supportsDuplicateZoneNames();
 
diff --git a/core/src/test/java/denominator/DynamicCredentialsProviderExampleTest.java b/core/src/test/java/denominator/DynamicCredentialsProviderExampleTest.java
index 9075179b..be566ab0 100644
--- a/core/src/test/java/denominator/DynamicCredentialsProviderExampleTest.java
+++ b/core/src/test/java/denominator/DynamicCredentialsProviderExampleTest.java
@@ -4,7 +4,6 @@
 import org.junit.Test;
 import org.junit.rules.ExpectedException;
 
-import java.util.Arrays;
 import java.util.Collection;
 import java.util.Iterator;
 import java.util.LinkedHashMap;
@@ -27,6 +26,7 @@
 import static denominator.CredentialsConfiguration.checkValidForProvider;
 import static denominator.CredentialsConfiguration.credentials;
 import static denominator.Denominator.create;
+import static java.util.Arrays.asList;
 import static org.assertj.core.api.Assertions.assertThat;
 
 public class DynamicCredentialsProviderExampleTest {
@@ -68,9 +68,9 @@ public void testImplicitDynamicCredentialsUpdate() {
     DNSApiManager mgr = create(new DynamicCredentialsProvider());
     ZoneApi zones = mgr.api().zones();
     assertThat(zones.iterator())
-        .containsExactly(Zone.builder().name("acme").qualifier("wily").email("coyote").build());
+        .containsExactly(Zone.builder().name("acme").email("coyote").build());
     assertThat(zones.iterator())
-        .containsExactly(Zone.builder().name("acme").qualifier("road").email("runner").build());
+        .containsExactly(Zone.builder().name("acme").email("runner").build());
 
     // now, if the supplier doesn't supply a set of credentials, we should
     // get a correct message
@@ -118,9 +118,7 @@ public Iterator<Zone> iterator() {
       CustomerUsernamePassword cup = creds.get();
       // normally, the credentials object would be used to invoke a remote
       // command. in this case, we don't and say we did :)
-      return Arrays.asList(
-          Zone.builder().name(cup.customer).qualifier(cup.username).email(cup.password).build())
-          .iterator();
+      return asList(Zone.builder().name(cup.customer).email(cup.password).build()).iterator();
     }
 
     @Override
@@ -145,7 +143,7 @@ public String name() {
     @Override
     public Map<String, Collection<String>> credentialTypeToParameterNames() {
       Map<String, Collection<String>> options = new LinkedHashMap<String, Collection<String>>();
-      options.put("username", Arrays.asList("customer", "username", "password"));
+      options.put("username", asList("customer", "username", "password"));
       return options;
     }
 
@@ -158,9 +156,9 @@ public Map<String, Collection<String>> credentialTypeToParameterNames() {
     static class Module {
 
       final AtomicInteger credentialIndex = new AtomicInteger();
-      final List<List<String>> credentials = Arrays.asList(
-          Arrays.asList("acme", "wily", "coyote"),
-          Arrays.asList("acme", "road", "runner")
+      final List<List<String>> credentials = asList(
+          asList("acme", "wily", "coyote"),
+          asList("acme", "road", "runner")
       );
 
       /**
diff --git a/core/src/test/java/denominator/ReadOnlyLiveTest.java b/core/src/test/java/denominator/ReadOnlyLiveTest.java
index e80f24dc..5e81ddda 100644
--- a/core/src/test/java/denominator/ReadOnlyLiveTest.java
+++ b/core/src/test/java/denominator/ReadOnlyLiveTest.java
@@ -26,12 +26,9 @@ public void zoneIdentification() {
     assumeTrue("No zones to test", zones.hasNext());
     Zone zone = zones.next();
     if (manager.provider().supportsDuplicateZoneNames()) {
-      assertThat(zone.qualifier()).isNotNull();
       assertThat(zone.id())
           .isNotNull()
           .isNotEqualTo(zone.name());
-    } else {
-      assertThat(zone).hasNoQualifier();
     }
   }
 
diff --git a/dynect/src/test/java/denominator/dynect/DynECTZoneApiMockTest.java b/dynect/src/test/java/denominator/dynect/DynECTZoneApiMockTest.java
index 9514689e..9b0e2fc2 100644
--- a/dynect/src/test/java/denominator/dynect/DynECTZoneApiMockTest.java
+++ b/dynect/src/test/java/denominator/dynect/DynECTZoneApiMockTest.java
@@ -28,7 +28,7 @@ public void iteratorWhenPresent() throws Exception {
     ZoneApi api = server.connect().api().zones();
 
     assertThat(api.iterator()).containsExactly(
-        Zone.builder().name("denominator.io").id("denominator.io.").email("fake@denominator.io.")
+        Zone.builder().name("denominator.io").id("denominator.io").email("fake@denominator.io.")
             .ttl(1800).build()
     );
 
diff --git a/model/src/main/java/denominator/model/Zone.java b/model/src/main/java/denominator/model/Zone.java
index 28bf8af4..1848624d 100644
--- a/model/src/main/java/denominator/model/Zone.java
+++ b/model/src/main/java/denominator/model/Zone.java
@@ -13,14 +13,12 @@
 public class Zone {
 
   private final String name;
-  private final String qualifier;
   private final String id;
   private final String email;
   private final int ttl;
 
-  Zone(String name, String qualifier, String id, String email, int ttl) {
+  Zone(String name, String id, String email, int ttl) {
     this.name = checkNotNull(name, "name");
-    this.qualifier = qualifier;
     this.id = id;
     this.email = checkNotNull(email, "email of %s", name);
     checkArgument(ttl >= 0, "Invalid ttl value: %s, must be 0-%s", ttl, Integer.MAX_VALUE);
@@ -37,24 +35,10 @@ public String name() {
     return name;
   }
 
-  /**
-   * A user-defined unique string that differentiates zones with the same name. Only supported when
-   * the {@code denominator.Provider#supportsDuplicateZoneNames()}.
-   *
-   * @return qualifier or null if the provider doesn't support multiple zones with the same name.
-   * @since 4.5
-   */
-  public String qualifier() {
-    return qualifier;
-  }
-
   /**
    * The potentially transient and opaque string that uniquely identifies the zone. This may be null
    * when used as an input object.
    *
-   * <p/>Note that this is not used in {@link #hashCode()} or {@link #equals(Object)}, as it may
-   * change over time.
-   *
    * @since 4.5
    */
   public String id() {
@@ -96,7 +80,7 @@ public boolean equals(Object obj) {
     if (obj instanceof Zone) {
       Zone other = (Zone) obj;
       return name().equals(other.name())
-             && equal(qualifier(), other.qualifier())
+             && equal(id(), other.id())
              && email().equals(other.email())
              && ttl() == other.ttl();
     }
@@ -107,7 +91,7 @@ && email().equals(other.email())
   public int hashCode() {
     int result = 17;
     result = 31 * result + name().hashCode();
-    result = 31 * result + (qualifier() != null ? qualifier().hashCode() : 0);
+    result = 31 * result + (id() != null ? id().hashCode() : 0);
     result = 31 * result + email().hashCode();
     result = 31 * result + ttl();
     return result;
@@ -118,9 +102,6 @@ public String toString() {
     StringBuilder builder = new StringBuilder();
     builder.append("Zone [");
     builder.append("name=").append(name());
-    if (qualifier() != null) {
-      builder.append(", ").append("qualifier=").append(qualifier());
-    }
     if (!name().equals(id())) {
       builder.append(", ").append("id=").append(id());
     }
@@ -131,8 +112,7 @@ public String toString() {
   }
 
   /**
-   * Represent a zone without a {@link #qualifier() qualifier} when its {@link #id() id} is its
-   * name.
+   * Represent a zone when its {@link #id() id} is its name.
    *
    * @param name corresponds to {@link #name()} and {@link #id()}
    * @deprecated Use {@link #builder()}. This will be removed in version 5.
@@ -143,7 +123,7 @@ public static Zone create(String name) {
   }
 
   /**
-   * Represent a zone without a {@link #qualifier() qualifier}.
+   * Represent a zone with a fake email and defaul ttl of 86400.
    *
    * @param name corresponds to {@link #name()}
    * @param id   corresponds to {@link #id()}
@@ -151,7 +131,7 @@ public static Zone create(String name) {
    */
   @Deprecated
   public static Zone create(String name, String id) {
-    return new Zone(name, null, id, "fake@" + name, 86400);
+    return new Zone(name, id, "fake@" + name, 86400);
   }
 
   public static Builder builder() {
@@ -164,7 +144,6 @@ public static Builder builder() {
   public static final class Builder {
 
     private String name;
-    private String qualifier;
     private String id;
     private int ttl = 86400;
     private String email;
@@ -177,14 +156,6 @@ public Builder name(String name) {
       return this;
     }
 
-    /**
-     * @see Zone#qualifier()
-     */
-    public Builder qualifier(String qualifier) {
-      this.qualifier = qualifier;
-      return this;
-    }
-
     /**
      * Can be null for input objects.
      *
@@ -214,7 +185,7 @@ public Builder ttl(Integer ttl) {
     }
 
     public Zone build() {
-      return new Zone(name, qualifier, id, email, ttl);
+      return new Zone(name, id, email, ttl);
     }
   }
 }
diff --git a/model/src/test/java/denominator/assertj/ZoneAssert.java b/model/src/test/java/denominator/assertj/ZoneAssert.java
index 34e1498a..0e65f355 100644
--- a/model/src/test/java/denominator/assertj/ZoneAssert.java
+++ b/model/src/test/java/denominator/assertj/ZoneAssert.java
@@ -19,12 +19,6 @@ public ZoneAssert hasName(String expected) {
     return this;
   }
 
-  public ZoneAssert hasQualifier(String expected) {
-    isNotNull();
-    objects.assertEqual(info, actual.qualifier(), expected);
-    return this;
-  }
-
   public ZoneAssert hasId(String expected) {
     isNotNull();
     objects.assertEqual(info, actual.id(), expected);
@@ -42,10 +36,4 @@ public ZoneAssert hasTtl(Integer expected) {
     objects.assertEqual(info, actual.ttl(), expected);
     return this;
   }
-
-  public ZoneAssert hasNoQualifier() {
-    isNotNull();
-    objects.assertNull(info, actual.qualifier());
-    return this;
-  }
 }
diff --git a/model/src/test/java/denominator/model/ZoneTest.java b/model/src/test/java/denominator/model/ZoneTest.java
index 7d17eb3b..8185bdc9 100644
--- a/model/src/test/java/denominator/model/ZoneTest.java
+++ b/model/src/test/java/denominator/model/ZoneTest.java
@@ -15,53 +15,29 @@ public class ZoneTest {
   public void factoryMethodsWork() {
     Zone name = Zone.create("denominator.io.");
     Zone id = Zone.create("denominator.io.", "ABCD");
-    Zone qualifier = Zone.builder()
-        .name("denominator.io.")
-        .qualifier("Test-Zone")
-        .id("ABCD")
-        .email("fake@denominator.io.").build();
 
     assertThat(name)
         .hasName("denominator.io.")
-        .hasNoQualifier()
         .hasId("denominator.io.")
         .isEqualTo(name)
-        .isEqualTo(id)
-        .isNotEqualTo(qualifier);
+        .isNotEqualTo(id);
 
     assertThat(name.hashCode())
-        .isEqualTo(id.hashCode())
-        .isNotEqualTo(qualifier.hashCode());
-    assertThat(name.toString()).isEqualTo("Zone [name=denominator.io., email=fake@denominator.io., ttl=86400]");
+        .isNotEqualTo(id.hashCode());
+    assertThat(name.toString())
+        .isEqualTo("Zone [name=denominator.io., email=fake@denominator.io., ttl=86400]");
 
     assertThat(id)
         .hasName("denominator.io.")
-        .hasNoQualifier()
         .hasId("ABCD")
         .isEqualTo(id)
-        .isEqualTo(name)
-        .isNotEqualTo(qualifier);
+        .isNotEqualTo(name);
 
     assertThat(id.hashCode())
-        .isEqualTo(name.hashCode())
-        .isNotEqualTo(qualifier.hashCode());
-
-    assertThat(id.toString()).isEqualTo("Zone [name=denominator.io., id=ABCD, email=fake@denominator.io., ttl=86400]");
-
-    assertThat(qualifier)
-        .hasName("denominator.io.")
-        .hasQualifier("Test-Zone")
-        .hasId("ABCD")
-        .isEqualTo(qualifier)
-        .isNotEqualTo(name)
-        .isNotEqualTo(id);
-
-    assertThat(qualifier.hashCode())
-        .isNotEqualTo(name.hashCode())
-        .isNotEqualTo(id.hashCode());
+        .isNotEqualTo(name.hashCode());
 
-    assertThat(qualifier.toString())
-        .isEqualTo("Zone [name=denominator.io., qualifier=Test-Zone, id=ABCD, email=fake@denominator.io., ttl=86400]");
+    assertThat(id.toString()).isEqualTo(
+        "Zone [name=denominator.io., id=ABCD, email=fake@denominator.io., ttl=86400]");
   }
 
   @Test
diff --git a/route53/src/main/java/denominator/route53/ListHostedZonesResponseHandler.java b/route53/src/main/java/denominator/route53/ListHostedZonesResponseHandler.java
index 1fe7bf17..f4e3238d 100644
--- a/route53/src/main/java/denominator/route53/ListHostedZonesResponseHandler.java
+++ b/route53/src/main/java/denominator/route53/ListHostedZonesResponseHandler.java
@@ -28,8 +28,6 @@ public void endElement(String uri, String name, String qName) {
       zone.name = currentText.toString().trim();
     } else if (qName.equals("Id")) {
       zone.id = currentText.toString().trim().replace("/hostedzone/", "");
-    } else if (qName.equals("CallerReference")) {
-      zone.callerReference = currentText.toString().trim();
     } else if (qName.equals("HostedZone")) {
       zones.add(zone);
       zone = new HostedZone();
diff --git a/route53/src/main/java/denominator/route53/Route53.java b/route53/src/main/java/denominator/route53/Route53.java
index 5b2905dd..a31d6a1a 100644
--- a/route53/src/main/java/denominator/route53/Route53.java
+++ b/route53/src/main/java/denominator/route53/Route53.java
@@ -47,7 +47,6 @@ class HostedZone {
 
     String id;
     String name;
-    String callerReference;
   }
 
   class HostedZoneList extends ArrayList<HostedZone> {
diff --git a/route53/src/main/java/denominator/route53/Route53ZoneApi.java b/route53/src/main/java/denominator/route53/Route53ZoneApi.java
index 58c20457..ae56a2fa 100644
--- a/route53/src/main/java/denominator/route53/Route53ZoneApi.java
+++ b/route53/src/main/java/denominator/route53/Route53ZoneApi.java
@@ -51,7 +51,6 @@ private Zone zipWithSOA(HostedZone next) {
     SOAData soaData = (SOAData) soa.get(0).records().get(0);
     return Zone.builder()
         .name(next.name)
-        .qualifier(next.callerReference)
         .id(next.id)
         .ttl(soaData.minimum())
         .email(soaData.rname()).build();
diff --git a/route53/src/test/java/denominator/route53/Route53DecoderTest.java b/route53/src/test/java/denominator/route53/Route53DecoderTest.java
index cb49a43b..8e36889a 100644
--- a/route53/src/test/java/denominator/route53/Route53DecoderTest.java
+++ b/route53/src/test/java/denominator/route53/Route53DecoderTest.java
@@ -52,9 +52,9 @@ public void decodeZoneListWithNext() throws Exception {
         + "  <MaxItems>10</MaxItems>\n"
         + "</ListHostedZonesResponse>"), HostedZoneList.class);
 
-    assertThat(result).extracting("name", "callerReference", "id").containsExactly(
-        tuple("example.com.", "a_unique_reference", "Z21DW1QVGID6NG"),
-        tuple("example2.com.", "a_unique_reference2", "Z2682N5HXP0BZ4")
+    assertThat(result).extracting("name", "id").containsExactly(
+        tuple("example.com.", "Z21DW1QVGID6NG"),
+        tuple("example2.com.", "Z2682N5HXP0BZ4")
     );
 
     assertThat(result.next).isEqualTo("Z333333YYYYYYY");
diff --git a/route53/src/test/java/denominator/route53/Route53ZoneApiMockTest.java b/route53/src/test/java/denominator/route53/Route53ZoneApiMockTest.java
index d3ad9993..c8fbcc79 100644
--- a/route53/src/test/java/denominator/route53/Route53ZoneApiMockTest.java
+++ b/route53/src/test/java/denominator/route53/Route53ZoneApiMockTest.java
@@ -58,7 +58,6 @@ public void iteratorWhenPresent() throws Exception {
 
     assertThat(domains.next())
         .hasName("denominator.io.")
-        .hasQualifier("denomination")
         .hasId("Z1PA6795UKMFR9")
         .hasEmail("awsdns-hostmaster.amazon.com.")
         .hasTtl(86400);
@@ -153,9 +152,9 @@ public void iterateByNameWhenPresent() throws Exception {
 
     ZoneApi api = server.connect().api().zones();
     assertThat(api.iterateByName("denominator.io.")).containsExactly(
-        Zone.builder().name("denominator.io.").qualifier("Foo").id("Z2ZEEJCUZCVG56")
+        Zone.builder().name("denominator.io.").id("Z2ZEEJCUZCVG56")
             .email("awsdns-hostmaster.amazon.com.").ttl(86400).build(),
-        Zone.builder().name("denominator.io.").qualifier("Bar").id("Z3OQLQGABCU3T")
+        Zone.builder().name("denominator.io.").id("Z3OQLQGABCU3T")
             .email("awsdns-hostmaster.amazon.com.").ttl(86400).build()
     );